The present invention relates to a dietary composition produced by a process involving extruding a protein containing product and water through an extruder at about 50-about 450 rpm and at a temperature of about 40° to about 120° C. to produce the dietary composition, wherein the residence time of the protein containing product (e.g., whey protein isolate) in the extruder is about 15-about 90 seconds, wherein the dietary composition contains partially denatured protein containing product or totally denatured protein containing product or mixtures thereof. The present invention also concerns a food product containing at least one food ingredient and a dietary fiber composition. The food product is produced by a process involving extruding the dietary composition and at least one food ingredient and water to produce the food product; the dietary composition is produced by a process involving extruding a protein containing product and water through an extruder to produce the dietary composition, wherein the dietary composition contains partially denatured protein containing product or totally denatured protein containing product or mixtures thereof.
As the reports of the health and nutraceutical benefits of consuming dietary fibers continue to grow, research is focused on increasing the amount, content and quality of fibers in human diet. Consumers as well as nutrition-focused professional organizations are demanding increased amounts of fiber in processed foods. The results of recent surveys of the amount of fiber consumed by Americans reveal that most consume less than 50% of the estimated desirable daily fiber intake. Current average fiber intake is estimated at about 12 g/day, but the American Dietetic Association recommends 20-35 g/day (J. Am. Dietetic Assoc., 93: 1446-1447 (1993)).
Foods rich in fiber help with the management of a host of conditions. Associated healthful benefits of increasing fiber consumption include reduced risk of some types of cancer (including breast cancer) and coronary heart disease, regulation of blood glucose and insulin, lowering the concentration of blood lipids, reduced risk of cardiovascular disease and controlling diabetes, alleviating constipation, hemorrhoids and diverticulitis (Wolk, A., et al., JAMA, 281(21): 1998-2004 (1999); Kritchevsky, D., Cereal Foods World, 42(2): 81-85 (1977)). Thus it is desirable and beneficial to increase the amount of fiber in most prepared foods.
The Food and Agricultural Organization/World Health Organization (FAO/WHO), 1995 Codex Alimentarius Commission defines dietary fiber as, “the edible plant or animal material not hydrolyzed by the endogenous enzymes of the human digestive tract as determined by the agreed upon method.” Typical fiber sources are plant-based and include grains, fruits and vegetables; other less-traditional food fibers include Chitosan, a fat-binding dietary fiber derived from shellfish, and polymeric components such as cell-wall proteins and phenolic compounds such as tannin and cutin.
Traditionally, the food industry uses native (folded) whey proteins for their functional and nutritional properties in formulating different foods. Though new products incorporating whey proteins, such as sports drinks, are being developed, innovation in process and product development is still needed (Anon., American Dairy Products Institute, Bulletin No. 25, p. 17 (2000)). Fortifying snacks with whey proteins could provide a particularly attractive outlet for surplus whey proteins; however, this practice has been limited due to known adverse textural effects when the whey protein concentrate supplementation is greater than 10% of the main starch component (Kim, C. H., and J. A. Maga, Lebensmittel-Wissenchaft und-Technologie, 20: 311-318 (1987)).
The present invention provides, in one aspect, proteins (e.g., whey proteins) that are totally denatured and are insoluble to enzymes and protein cleaving chemicals (e.g., urea). The new product is indigestible and can therefore serve as a fiber source. The fiber-like product described in this invention may be from an animal source (e.g., milk), but its properties are physiologically similar to plant-source dietary fiber, thus serving as a bulking agent and being nondigestible to enzymes. Alternate use for this product include use in biodegradable products and utilization in ingredients that require low gelling temperatures.